*Funky* DNS questions

[Barry Margolin]

In article <3908821b.66370956 at news.uswest.net>,
Jon <jonm.sportsmvp at com.spam.sux.my.butt.com> wrote:
>I have a couple of questions about DNS, specifically BIND for Linux. 
>
>Is it possible to set up a SINGLE DNS server such that you get
>different lookup results depending on your source IP address? In other
>words, when machine A does a nslookup on funky.domain.com it gets an
>internal IP address, and when machine B does a nslookup on the SAME
>name, funky.domain.com it get's a different IP for a different server?

BIND doesn't currently have this capability, but something called "views"
is supposed to be coming in BIND 9, and I believe it will support this.

You can get close, though.  There's a "sortlist" option that allows you to
specify the order in which records will be returned.  Since many
applications only use the first address in the response, sorting the
responses may achieve your goal.

>Second, if this is possible, and assuming I'm using a version of NAMED
>that supports dynamic updates, can the changes for each machine be
>dynamic (done without performing a reload on named)? I understand
>there might be a performance hit, but it's not really important for
>what I'm attempting to do.

If you use "sortlist", it shouldn't matter whether the entries were created
dynamically or statically.

A better solution may be to run multiple DNS servers.  If you only have a
single machine, you can still do it by using virtual addresses.  You run
multiple named processes on the same machine, pointing them to different
named.conf files, which will have different "listen-on" options so that
they operate on different IP addresses, and different versions of the zone
files.  Tell machine A to use one IP address as its nameserver, and tell B
to use the other one, and arrange for the dynamic updates to go to the
appropriate address.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
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